A dual-port dual-polarized compact microstrip antenna
for avoiding cross coupling between the two frequency bands is proposed
and analyzed. This antenna offers channel isolation better than 25 dB,
and is more compact compared to a conventional rectangular patch.
Analytical equations for calculating the resonant frequencies at both
ports are also presented. The theoretical calculations are verified using
experimental results

Files in this item: 1

Yeasts are ubiquitous in their distribution and populations mainly depend on the
type and concentration of organic materials. The distribution of species, as well as
their numbers and metabolic characteristics were found to be governed by existing
environmental conditions. Marine yeasts were first discovered from the Atlantic
Ocean and following this discovery, yeasts were isolated from different sources, viz.
seawater, marine deposits, seaweeds, fish, marine mammals and sea birds. Nearshore
environments are usually inhabited by tens to thousands of cells per litre of
water, whereas low organic surface to deep-sea oceanic regions contain 10 or fewer
cells/litre. Aerobic forms are found more in clean waters and fermentative forms in
polluted waters. Yeasts are more abundant in silty muds than in sandy sediments.
The isolation frequency of yeasts fell as the depth of the sampling site is increased.
Major genera isolated in this study were Candida, Cryptococcus, Debaryomyces and
Rhodotorula. For biomass estimation ergosterol method was used. Classification and
identification of yeasts were performed using different criteria, i.e. morphology, sexual
reproduction and physiological/biochemical characteristics. Fatty acid profiling or
molecular sequencing of the IGS and ITS regions and 28S gene rDNA ensured
accurate identification.

Files in this item: 1

Manjusha, S; Dr.Sarita,Bhat G(Cochin University of Science and Technology, December , 2006)

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Abstract:

While the seriousness of the problem of antibiotic resistance is now
recognized, the complex web of resistance linking humans, animals, and the
environment is getting realized. More often, antibiotics are used as a preventive
measure against diseases. Antibiotic use for agriculture leads to the increased
resistance in the environment since antibiotics are inevitable element during
agriculture/aquaculture and antibiotic residues are excreted as waste that is frequently
spread onto farmland as organic fertilizer. Fecal bacteria survive long periods in the
environment and spread through runoff into groundwater, rivers, and marine
ecosystems.However, horizontal gene transfer occurs in the animals and guts of humans and
in a variety of ecosystems, creating a pool of resistance in the rice fields and open
waters. Even if people are not in direct contact with resistant disease through food
animals, there are chances of contact with resistant fecal pathogens from the
environment. Additionally, pathogens that are autochthonous to the environment can
acquire resistance genes from the environment. Our study revealed that autochthonous
,
bacteria Vibrio spp gained antibiotic resistance in the environment. Further, it was
evident that horizontal gene transfer occurs in Vibrio by means of plasmids, which
further augments the gravity of the problem. Non-pathogenic bacteria may also
acquire resistance genes and serve as a continuing source of resistance for other
bacteria, both in the environment, and in the human gut. As the effectiveness of
antibiotics for medical applications decline, the indiscriminate use of in aquaculture
and in humans can have disastrous conditions in future due to horizontal gene transfer
and the spread of resistant organisms: We must recognize and deal with the threat
posed by overuse of antibiotics.

Description:

Department of Biotechnology,
Cochin University of Science and Technology